Selective hydrogenation of cyclododecatriene to cyclododecene



ilnited States SELECTIVE HYDROGENATTQN F CYCLODG- DECATRHENE TO(lYKILGDUDECENE Herbert K. Wiese, Cranford, and fiamuel B. Lippincott,

Springfield, NJ, assignors to Esso Research and Engineering Company, acorporation of Delaware No Drawing. Filed Apr. 7, 1959, Ser. No.804,6ll6

18 Claims. ((311. 260-666) The present invention relates to an improvedprocess for the selective hydrogenation of a polyolefin or an acetyleneto an olefinic material more highly saturated than the startingmaterial. More particularly, the present invention relates tohydrogenating this more highly unsaturated than a monoolefin materialwith a high surface area catalyst in the presence of a displacementsolvent to obtain a selective hydrogenation to the desired materials.Although it is not intended to limit this'invention to any mechanism forits accomplishment, it is theorized that this displacement solvent isstrongly adsorbed on the high surface area catalyst thus obtaining aselective displacement from the catalyst surface of the less stronglyadsorbed monoolefins preferentially to the more strongly adsorbed morehighly unsaturated feed material. This, of course, produces the desiredselective hydrogenation to olefins rather than to paraflins. In separatepreferred embodiments the hydrogen may be supplied as gaseous hydrogen,as a hydrogen transfer agent, or as gaseous hydrogen plus a hydrogentransfer agent. Most particularly, the present invention relates toselectively hydrogenating cyclododecatriene to cyclododecene utilizingonly a secondary alcohol both to supply the hydrogen and to produce thedisplacement solvent in situ. Thus, the alcohol acts both as a hydrogentransfer agent and additionally is converted to a ketone said ketonethen acting as the displacement solvent.

Prior to the present it has been known that all attempts to hydrogenatematerials such as cyclic trienes, aromatics and diolefins with orwithout metallic catalysts invariably resulted in a comparativelynon-selective hydrogenation to a mixture of saturated and unsaturatedmaterials. Additionally, with respect to materials such ascyclododecatriene, which contains 1 cis double bond and 2 trans doublebonds in its most commonly prepared form, it was found that the cisdouble bond hydrogenated faster than the trans double bonds. Thus, whenit was attempted to obtain cyclododecene, cyclododecadienepreferentially to cyclododecene was obtained along with cyclododecane.Surprisingly, a method has now been developed Which can be used toobtain selective hydrogenation as, for example, of cyclododecatriene tocyclododecene in very high yields in the order of selectivities of atleast 86% along with conversions of about 95%.

The 1,5,9-cyclododecatriene preferred material to be selectivelyhydrogenated according to this invention is known in the art, beingprepared by trimerizing butadiene with alkyl metal type catalysts. Itspreparation and description is described for example in AngewandteChemie, V. 69, No. 112397 (June 7, 1957). Although four stereo isomersof 1,5,9-cyclododecatriene are theoretically possible only two have thusfar been isolated. These are the "ice cis, trans, trans (cis., tr., tr.)and the trans, trans, trans (tr., tr., tr.) as shown by the formulasbelow.

Throughout this specification it will be assumed that either of theisomers above represented or of the other isomers may be utilized ormixtures thereof.

According to the present invention it is contemplated that materialsmore unsaturated than olefins such as triolefins, conjugated andunconjugated diolefins, cyclic diolefins, aromatics and acetylenes canbe selectively hydrogenated to more saturated compounds of a particularunsaturation type such as monoolefins, diolefins, etc. Thus, diolefinsand acetylenes may be converted to olefins and triolefins can beconverted to diolefins or to monoolefins whichever product is desired.This is possible merely by selecting the proper displacing agent andstoichiometric amounts of hydrogen. Since monoolefins are less stronglyadsorbed than diolefins and diolefins are less strongly adsorbed thantriolefins it is necessary for example, if one wants to hydrogenate atriolefin to a diolefin, to select a displacing agent that selectivelydesorbs the diolefins as soon as they are formed from the triolefins. Itshould be noted that in each case selective hydrogenation to the desiredcompound is obtained rather than bydrogenation to obtain a mixture ofsaturated and unsaturated compounds. It is further contemplated that thepresent invention process will be useful also in selectivelyhydrogenating mixtures of unsaturated and saturated materials, such as,for example, in gasolines of undesirable acetylenes and diolefins toolefins, thus increasing the stability of the gasoline withoutdecreasing the octane number thereof. In prior art hydrogenations thiscouldonly be done at the expense of converting considerable amounts ofhigh octane olefins to low octane parafiins.

The feed stocks which may be utilized in the present invention willpreferably be C to C unsaturates. The high surface area catalysts usedmay be nickel such as Raney nickel or nickel deposited on kieselguhr,alumina or silica. Other materials such as iron, cobalt, copper,

, palladium, platinum, molybdenum, tungsten and chromium as well astheir oxides or sulfides may also be utilized alone or disposed on highsurface area bases. These high surface area catalysts have surface areasin the range of 1-500, preferably 5-100 sq. meters per gram. The organicdisplacement solvents which are more strongly adsorbed on the catalystthan are the monoolefins which may be utilized in this invention are asfollows (listed in the order in which they are preferred): (1)

ketones or aldehydes, (2) amine type compounds such as pyridine,piperidine, mono and dimethyl aniline, (3) phenol type compounds such asphenol, hydroquinone, naphthol and cresol and (4) ether type compoundssuch as dialkyl ethers, dioxane, tetrahydrofuran, and (5) nitriles.Preferably these materials should be lower molecuar weight materials inthe range of C -C Most preferably, it is preferred to utilize acetone ormethyl ethyl ketone. The amount of displacement solvent utilized shouldbe at least sutficient to saturate the catalyst in the absence of othermaterials. Preferably amounts of the displacement solvent should be inthe range of less than 1 to greater than 100% based upon the olefinicmaterial to be hydrogenated. It should be noted that although a largenumber of different feed stocks may be hydrogenated according to thisinvention that the displacement solvent need only be selected todisplace the mono or diolefins from the catalyst and therefore generallythe same solvents can be utilized regardless of the feed stock beingtreated. Reaction temperatures will range from 20-400 C., preferably120-250 C. and pressures may be from 1-100 atmospheres. In most cases itwill be preferred to utilize enough pressure to obtain a liquid phasereaction of the reactants. It is preferred to utilize stoichiometricamounts of the hydrogen source supplied whether in the form of gaseoushydrogen or as a hydrogen transfer agent, to obtain the desiredhydrogenation of one double bond or of two double bonds. Alternatively,of course, it is also contemplated that excess hydrogen as gaseoushydrogen or hydrogen donor material may be utilized with limitation ofreaction times to obtain the desired amount of hydrogenation, i. e.hydrogenation of one double bond or of two double bonds only. Forexample, when using isopropanol as hydrogen donor the rate of hydrogentransfer slows down as the acetone builds up in the reaction mixture.Therefore, if no provision is made for continuously removing theacetone, for example by continuously distilling off the acetone, anexcess of isopropanol over the stoichiometric amount is desirable fromthe standpoint of maintaining a high rate of hydrogen transfer.

Utilizing gaseous hydrogen as the source of hydrogen it is preferred toemploy temperatures in the range of 20- 250 C. preferably 100 to 200 C.and pressures of from 1 to 100 atmospheres. Any of the displacingsolvents mentioned above can be employed. In the case of acetone ormethylethyl ketone a mixture of the alcohol and corresponding ketone canalso be employed. A ratio of ketone to alcohol must be selected suchthat the rate of hydrogen transfer is negligible compared to the rate ofhydrogenation; that is the rate of addition of gaseous hydrogen to thedouble bond. This is more clearly demonstrated by a few rate data at 170C. using Raney' nickel as catalyst, isopropyl alcohol as hydrogen donorand cyclododecatriene as the unsaturated compound. The rates of hydrogentransfer as a function of the amount of isopropanol converted to acetoneare as follows.

\ Rate of gaseous hydrogen addition to cyclododecatriene. 7

Although the absolute rates vary with each batch of nickel the relativerates remain about the same. .It is evident from these data that a :50or greater mixture of acetone: isopropanol can be used as displacingsolvent when using gaseous hydrogen as the source of hydrogen.

The preferred hydrogen donors utilized are alcohols (primary orpreferably secondary alcohols), tetralin or other partially orcompletely hydrogenated fused ring aromatic hydrocarbons or single ringpartially or fully hydrogenated aromatics. Most preferably the hydrogendonor will be cyclododecanol, cyclohexanol, secondary butanol orisopropanol or materials which produce a selective solvent in situ. Withisopropyl and with secondary butyl alcohol hydrogen donors,pressurization is preferred to maintain these materials in their liquidstate at reaction temperatures.

The reaction when using a secondary alcohol as hydrogen donor may beillustrated by the following equation.

Q 2RCHOHR') Q In the above equation R and R may be alkyl or aryl groupsor may be joined to form a ring compound. As is evident from theequation secondary alcoholis convertedto a ketone. Although this ketonecan be rehydrogenated to the alcohol to obtain a continuous process,alternatively it may be preferred to utilize the ketone as such in otherprocesses or for sale as a final product. A particular advantage of theuse of hydrogen donors to supply hydrogen to the process is that thisprovides an efficient economical control of the amount of hydrogen addedso as to obtain the selective hydrogenation desired. Thus, approximatelystoichiometric amounts of the hydrogen transfer agent are used to obtainthe saturation desired. Utilizing hydrogen donor reactants temperaturesin the range of 100400 C. preferably l20-250 C. and pressures of froml20 atmospheres are preferred. It is also contemplated that mixtures ofa hydrogen transfer agent and a separate displacing solvent may be used.

Where both hydrogen transfer agents and hydrogen are utilizedtemperatures will be in the range of 20400 C. and pressures will be inthe range of l-lOO atmospheres.

An advantage for the use of both hydrogen transfer agents and gaseoushydrogen is that in case one does not want to continuously removeacetone when using isopropanol and at the same time maintain a high rateof hydrogenation, gaseous hydrogen can be added as soon as the hydrogentransfer rate becomes too slow form an economic standpoint.

The present invention will be more clearly understood from aconsideration of the following examples which present data obtained inthe laboratory.

Example 1 -was flushed with nitrogen, pressured to 300500 p.s.i.g.

withnitrogen and was heated, while being agitated, to the specifiedtemperature for the specified time. In the cases where molecularhydrogen was used it was introduced intermittently to maintain pressurewithin the specified limits. Also, for comparison hydrogenation usingPtO; as catalyst and gaseous hydrogen was also conducted.

u No 1 2 3 4 s 7 8 $011109 05 Hydrogen H2 H2 H3 H2 Cyclodo- Cyclo-Second- Isoprodecanol hexanol ary panol Butanol yst PtO Pro, Ni Ni d Nid Ni Nl Ni Percent Catalyst z .2 .2 s 2 2 2 a 2 p ratur C 30-50 30-5030-50 170 b 185 h 170 b 170 b 170 Pressure, p.s.i.g -50 20-50 20-50 f 1,000 400 u 300 l 350 300 Length r11 1,hours 0.75 0. 75 4. 5 4. 5 5. 5 5.0 3. 5 3. 5 rsi n. pcrcenL. 34 56 95 9s 99 88 96 72 Selectivity to: o

cy lodod cadiene 70 61 22 31 3 3s 7 45 y l d decene 22 29 56 63 88 02 so52 Cycoldodecane 8 10 22 6 9 2 7 3 I Nitrogen pressure.

b Maximum temperature.

= Determined by mass spectra analysis.

5 Commercial Raney nickel dispersed in water. most cases by washing withthe alcohol used as hydrogen donor.

6 Acetone used as displacing solvent.

1 Pressure at beginning of run. Dropped to zero at end of run.

2 Based on cyclododecatriene.

The data shown in the table clearly demonstrate the selectivehydrogenation. With cyclodecanol and secondary butanol as hydrogendonors the selectivity to cyclododecene was 88 and 86% at conversionlevels of 99 and 96% respectively. The selectivity to cyclododecane wasless than 10% in either run. With isopropanol as hydrogen donor theconversion was only 72% due to the decrease in rate as a result ofacetone buildup but as the data indicate the hydrogenation wasselective. This is evident by comparing the selectivity to cyclododeceneand cyclododecane in this run with the selectivities in the 56%conversion run using gaseous hydrogen and Pt0 as catalyst and the 95%conversion run (Run 3) using Raney nickel. That gaseous hydrogen can beemployed in the presence of acetone is evident from Run 4. Thus it canbe seen that selectivity using hydrogen in the presence of acetone ismuch better than that obtained in any of the hydrogenation only runs.Particularly, Run 3 shows poor selectivity due to the high level ofcyclododecane obtained, i.e. 22% as compared to only 6% where an acetonedisplacement solvent is used.

What is claimed is:

1. The process for the selective hydrogenation of a C -C hydrocarbonmore unsaturated than a monoolefin to an olefinic C -C hydrocarbon moresaturated than the starting material which comprises reacting the moreunsaturated hydrocarbon with at least the stoichiometric amount of ahydrogen source selected from the group consisting of C -C saturatedaliphatic monohydric alcohols, C -C saturated cyclic monohydricalcohols, and mixtures of each of these materials with gaseous hydrogento obtain hydrogenation to the desired olefinic material in the presenceof a high surface area hydrogenation catalyst.

2. The process of claim 1 in which the hydrogen source is gaseoushydrogen and a C -C aliphatic secondary alcohol. 7

3. The process of claim 1 in which the hydrogen source is gaseoushydrogen and a C -C cyclic alcohol.

4. The process of claim 1 in which the starting material is anon-conjugated diolefin.

5. The process of claim 1 in which the starting material iscyclododecatriene and in which selective hydrogenation is conducted toproduce preferentially cyclododecene. I

6. The process of claim 1 in which selective hydro- Water was removed bywash ing with acetone followed in the starting material which comprisesreacting the more unsaturated hydrocarbon with at least thestoichiometric amount of a c3'-C12 alcohol hydrogen transfer agentselected from the group consisting of saturated aliphatic monohydricalcohols and saturated cyclic monohydric alcohols to obtainhydrogenation to the desired olefinic material in the presence of a highsurface area hydrogenation catalyst.

8. The process of claim 7 in which the alcohol hydrogen transfer agentis a secondary alcohol.

9. The process of claim 7 in whichthe alcohol hydrogen transfer agent isa C -C secondary alcohol.

10. The process of claim 7 in which stoichiometric amounts of thealcohol to obtain the desired hydrogenation are utilized.

11. The process of claim 7 in which a diolefin is selectivelyhydrogenated to a monoolefin using stoichiometric amounts of the alcoholhydrogen transfer agent.

12. The process of claim 7 in which cyclododecatriene is selectivelyhydrogenated to cyclododecene utilizing stoichiometric amounts ofcyclododecanol as the hydrogen transfer agent.

13. The process of claim 7 in which cyclododecatriene is selectivelyhydrogenated to cyclododecene utilizing gcnation is conducted attemperatures of 20-400" C. and

stoichiometric amounts of cyclohexanol as a hydrogen transfer agent.

14. The process of claim 7 in which cyclododecatriene is selectivelyhydrogenated to cyclododecene utilizing stoichiometric amounts ofsecondary butanol as the hydrogen transfer agent.

15. The process of claim 7 in which cyclododecatriene is selectivelyhydrogenated to cyclododecene utilizing stoichiometric amounts ofisopropanol as the hydrogen transfer. agent.

16. The process of claim 7 in which cyclododecatriene is selectivelyhydrogenated to cyclododecene utilizing stoichiometric amounts of a C -Csecondary alcohol as the hydrogen transfer agent.

17. The process of claim 7 in which the alcohol hydrogen transfer agentis a cyclic alcohol.

18. The process of claim 7 in which selective hydrogenation is conductedat'temperatures of 20400 C. and pressures of from 1-100 atmospheres andin which stoichiometric amounts of the hydrogen transfer agent to obtainthe desired hydrogenation are utilized.

References Cited in the file 'of this patent UNITED STATES PATENTS

1. THE PROCESS FOR THE SELECTIVE HYDROGENATION OF A C3-C24 HYDROCARBONMORE UNSATURATED THAN A MONOOLEFIN TO AN OLEFINIC C3-C24 HYDROCARBONMORE SATURATED THAN THE STARTING MATERIAL WHICH COMPRISES REACTING THEMORE UNSATURATED HYDROCARBON WITH AT LEAST THE STOICHIOMETRIC AMOUNT OFA HYDROGEN SOURCE SELECTED FROM THE GROUP CONSISTING OF C3-C12 SATURATEDALIPHATIC MONOHYDRIC ALCOHOLS, C3-C12 SATURATED CYCLIC MONOHYDRICALCOHOLS, AND MIXTURES OF EACH OF THESE MATERIALS WITH GASEOUS HYDROGENTO OBTAIN HYDROGENATION TO THE DESIRED OLEFINIC MATERIAL IN THE PRESENCEOF A HIGH SURFACE AREA HYDROGENATION CATALYST.